/*
 * Tencent is pleased to support the open source community by making IoT Hub available.
 * Copyright (C) 2018-2020 Tencent. All rights reserved.

 * Licensed under the MIT License (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://opensource.org/licenses/MIT

 * Unless required by applicable law or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include "utils_sha1.h"

#include <stdlib.h>
#include <string.h>

#include "qcloud_iot_export_log.h"
#include "qcloud_iot_import.h"

/* Implementation that should never be optimized out by the compiler */
static void utils_sha1_zeroize(void *v, size_t n)
{
    volatile unsigned char *p = v;
    while (n--) {
        *p++ = 0;
    }
}

/*
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef IOT_SHA1_GET_UINT32_BE
#define IOT_SHA1_GET_UINT32_BE(n, b, i)                                                                     \
    {                                                                                                       \
        (n) = ((uint32_t)(b)[(i)] << 24) | ((uint32_t)(b)[(i) + 1] << 16) | ((uint32_t)(b)[(i) + 2] << 8) | \
              ((uint32_t)(b)[(i) + 3]);                                                                     \
    }
#endif

#ifndef IOT_SHA1_PUT_UINT32_BE
#define IOT_SHA1_PUT_UINT32_BE(n, b, i)            \
    {                                              \
        (b)[(i)]     = (unsigned char)((n) >> 24); \
        (b)[(i) + 1] = (unsigned char)((n) >> 16); \
        (b)[(i) + 2] = (unsigned char)((n) >> 8);  \
        (b)[(i) + 3] = (unsigned char)((n));       \
    }
#endif

void utils_sha1_init(iot_sha1_context *ctx)
{
    memset(ctx, 0, sizeof(iot_sha1_context));
}

void utils_sha1_free(iot_sha1_context *ctx)
{
    if (ctx == NULL) {
        return;
    }

    utils_sha1_zeroize(ctx, sizeof(iot_sha1_context));
}

void utils_sha1_clone(iot_sha1_context *dst, const iot_sha1_context *src)
{
    *dst = *src;
}

/*
 * SHA-1 context setup
 */
void utils_sha1_starts(iot_sha1_context *ctx)
{
    ctx->total[0] = 0;
    ctx->total[1] = 0;

    ctx->state[0] = 0x67452301;
    ctx->state[1] = 0xEFCDAB89;
    ctx->state[2] = 0x98BADCFE;
    ctx->state[3] = 0x10325476;
    ctx->state[4] = 0xC3D2E1F0;
}

void utils_sha1_process(iot_sha1_context *ctx, const unsigned char data[64])
{
    uint32_t temp, W[16], A, B, C, D, E;

    IOT_SHA1_GET_UINT32_BE(W[0], data, 0);
    IOT_SHA1_GET_UINT32_BE(W[1], data, 4);
    IOT_SHA1_GET_UINT32_BE(W[2], data, 8);
    IOT_SHA1_GET_UINT32_BE(W[3], data, 12);
    IOT_SHA1_GET_UINT32_BE(W[4], data, 16);
    IOT_SHA1_GET_UINT32_BE(W[5], data, 20);
    IOT_SHA1_GET_UINT32_BE(W[6], data, 24);
    IOT_SHA1_GET_UINT32_BE(W[7], data, 28);
    IOT_SHA1_GET_UINT32_BE(W[8], data, 32);
    IOT_SHA1_GET_UINT32_BE(W[9], data, 36);
    IOT_SHA1_GET_UINT32_BE(W[10], data, 40);
    IOT_SHA1_GET_UINT32_BE(W[11], data, 44);
    IOT_SHA1_GET_UINT32_BE(W[12], data, 48);
    IOT_SHA1_GET_UINT32_BE(W[13], data, 52);
    IOT_SHA1_GET_UINT32_BE(W[14], data, 56);
    IOT_SHA1_GET_UINT32_BE(W[15], data, 60);

#define S(x, n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))

#define R(t) \
    (temp = W[(t - 3) & 0x0F] ^ W[(t - 8) & 0x0F] ^ W[(t - 14) & 0x0F] ^ W[t & 0x0F], (W[t & 0x0F] = S(temp, 1)))

#define P(a, b, c, d, e, x)                \
    {                                      \
        e += S(a, 5) + F(b, c, d) + K + x; \
        b = S(b, 30);                      \
    }

    A = ctx->state[0];
    B = ctx->state[1];
    C = ctx->state[2];
    D = ctx->state[3];
    E = ctx->state[4];

#define F(x, y, z) (z ^ (x & (y ^ z)))
#define K          0x5A827999

    P(A, B, C, D, E, W[0]);
    P(E, A, B, C, D, W[1]);
    P(D, E, A, B, C, W[2]);
    P(C, D, E, A, B, W[3]);
    P(B, C, D, E, A, W[4]);
    P(A, B, C, D, E, W[5]);
    P(E, A, B, C, D, W[6]);
    P(D, E, A, B, C, W[7]);
    P(C, D, E, A, B, W[8]);
    P(B, C, D, E, A, W[9]);
    P(A, B, C, D, E, W[10]);
    P(E, A, B, C, D, W[11]);
    P(D, E, A, B, C, W[12]);
    P(C, D, E, A, B, W[13]);
    P(B, C, D, E, A, W[14]);
    P(A, B, C, D, E, W[15]);
    P(E, A, B, C, D, R(16));
    P(D, E, A, B, C, R(17));
    P(C, D, E, A, B, R(18));
    P(B, C, D, E, A, R(19));

#undef K
#undef F

#define F(x, y, z) (x ^ y ^ z)
#define K          0x6ED9EBA1

    P(A, B, C, D, E, R(20));
    P(E, A, B, C, D, R(21));
    P(D, E, A, B, C, R(22));
    P(C, D, E, A, B, R(23));
    P(B, C, D, E, A, R(24));
    P(A, B, C, D, E, R(25));
    P(E, A, B, C, D, R(26));
    P(D, E, A, B, C, R(27));
    P(C, D, E, A, B, R(28));
    P(B, C, D, E, A, R(29));
    P(A, B, C, D, E, R(30));
    P(E, A, B, C, D, R(31));
    P(D, E, A, B, C, R(32));
    P(C, D, E, A, B, R(33));
    P(B, C, D, E, A, R(34));
    P(A, B, C, D, E, R(35));
    P(E, A, B, C, D, R(36));
    P(D, E, A, B, C, R(37));
    P(C, D, E, A, B, R(38));
    P(B, C, D, E, A, R(39));

#undef K
#undef F

#define F(x, y, z) ((x & y) | (z & (x | y)))
#define K          0x8F1BBCDC

    P(A, B, C, D, E, R(40));
    P(E, A, B, C, D, R(41));
    P(D, E, A, B, C, R(42));
    P(C, D, E, A, B, R(43));
    P(B, C, D, E, A, R(44));
    P(A, B, C, D, E, R(45));
    P(E, A, B, C, D, R(46));
    P(D, E, A, B, C, R(47));
    P(C, D, E, A, B, R(48));
    P(B, C, D, E, A, R(49));
    P(A, B, C, D, E, R(50));
    P(E, A, B, C, D, R(51));
    P(D, E, A, B, C, R(52));
    P(C, D, E, A, B, R(53));
    P(B, C, D, E, A, R(54));
    P(A, B, C, D, E, R(55));
    P(E, A, B, C, D, R(56));
    P(D, E, A, B, C, R(57));
    P(C, D, E, A, B, R(58));
    P(B, C, D, E, A, R(59));

#undef K
#undef F

#define F(x, y, z) (x ^ y ^ z)
#define K          0xCA62C1D6

    P(A, B, C, D, E, R(60));
    P(E, A, B, C, D, R(61));
    P(D, E, A, B, C, R(62));
    P(C, D, E, A, B, R(63));
    P(B, C, D, E, A, R(64));
    P(A, B, C, D, E, R(65));
    P(E, A, B, C, D, R(66));
    P(D, E, A, B, C, R(67));
    P(C, D, E, A, B, R(68));
    P(B, C, D, E, A, R(69));
    P(A, B, C, D, E, R(70));
    P(E, A, B, C, D, R(71));
    P(D, E, A, B, C, R(72));
    P(C, D, E, A, B, R(73));
    P(B, C, D, E, A, R(74));
    P(A, B, C, D, E, R(75));
    P(E, A, B, C, D, R(76));
    P(D, E, A, B, C, R(77));
    P(C, D, E, A, B, R(78));
    P(B, C, D, E, A, R(79));

#undef K
#undef F

    ctx->state[0] += A;
    ctx->state[1] += B;
    ctx->state[2] += C;
    ctx->state[3] += D;
    ctx->state[4] += E;
}

/*
 * SHA-1 process buffer
 */
void utils_sha1_update(iot_sha1_context *ctx, const unsigned char *input, size_t ilen)
{
    size_t   fill;
    uint32_t left;

    if (ilen == 0) {
        return;
    }

    left = ctx->total[0] & 0x3F;
    fill = 64 - left;

    ctx->total[0] += (uint32_t)ilen;
    ctx->total[0] &= 0xFFFFFFFF;

    if (ctx->total[0] < (uint32_t)ilen) {
        ctx->total[1]++;
    }

    if (left && ilen >= fill) {
        memcpy((void *)(ctx->buffer + left), input, fill);
        utils_sha1_process(ctx, ctx->buffer);
        input += fill;
        ilen -= fill;
        left = 0;
    }

    while (ilen >= 64) {
        utils_sha1_process(ctx, input);
        input += 64;
        ilen -= 64;
    }

    if (ilen > 0) {
        memcpy((void *)(ctx->buffer + left), input, ilen);
    }
}

static const unsigned char iot_sha1_padding[64] = {0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                                                   0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                                                   0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

/*
 * SHA-1 final digest
 */
void utils_sha1_finish(iot_sha1_context *ctx, unsigned char output[20])
{
    uint32_t      last, padn;
    uint32_t      high, low;
    unsigned char msglen[8];

    high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
    low  = (ctx->total[0] << 3);

    IOT_SHA1_PUT_UINT32_BE(high, msglen, 0);
    IOT_SHA1_PUT_UINT32_BE(low, msglen, 4);

    last = ctx->total[0] & 0x3F;
    padn = (last < 56) ? (56 - last) : (120 - last);

    utils_sha1_update(ctx, iot_sha1_padding, padn);
    utils_sha1_update(ctx, msglen, 8);

    IOT_SHA1_PUT_UINT32_BE(ctx->state[0], output, 0);
    IOT_SHA1_PUT_UINT32_BE(ctx->state[1], output, 4);
    IOT_SHA1_PUT_UINT32_BE(ctx->state[2], output, 8);
    IOT_SHA1_PUT_UINT32_BE(ctx->state[3], output, 12);
    IOT_SHA1_PUT_UINT32_BE(ctx->state[4], output, 16);
}

/*
 * output = SHA-1( input buffer )
 */
void utils_sha1(const unsigned char *input, size_t ilen, unsigned char output[20])
{
    iot_sha1_context ctx;

    utils_sha1_init(&ctx);
    utils_sha1_starts(&ctx);
    utils_sha1_update(&ctx, input, ilen);
    utils_sha1_finish(&ctx, output);
    utils_sha1_free(&ctx);
}
